Issued  May  31,  1907. 

U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY.— BULLETIN  No.  100.    ' 

A.  D.  MELVIN,  CHIKF  OF  BUREAU. 


THE  GERMICIDAL  VALUE  OF 
LIQUOR  CRESOLIS  COMPOSITUS  (U.  S.  P.). 


BY 
C.  N.  McBRYDE,  M.  D., 

Bacteriologist,  Biochemic  Division. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1907. 


Property  of  the  United  'Sts 


Issued  May  31,  1907. 

U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY.—  BULLETIN  No.  100. 

A.  D.  MELV1N,  CHIEF  of  BUREAU. 


'     THE  GERMICIDAL  VALUE  OF 
LIQUOR  CRESOLIS  COMPOSITUS  (U.  S.  P.). 


BY 

C.  N.  McBRYDE,  M.  D., 
Bacteriologist,  Biochemic  Division, 


WASHINGTON : 

GOVERNMENT  PRINTING  OFFICE. 

1907. 


BUREAU  OF  ANIMAL  INDUSTRY. 


Chief:  A.  D.  M K.I.MS. 
Assistant  Chiif:  \.  M.  FARRIN<;T«>S. 
Chief  Clrrk:  K.  I*.  .1. 

Biochemic  Division:  M.  DOKHKT.  chief;  JAMES  A.  EMERY,  assistant  chief. 
7>airy  Division:  Ki>.  II.  WKHHTKR.  chief;  <'.  15.  LANK,  :i.-.»i-t:uit  chief. 
InxiKi-tion  Dii"ision:  RICE  P.  STKI»IM>M.  chief;  MOKIUK  WOODKS.  ;is.*i.«tant  chief. 
Pathological  l>ii  ixinn:  JOHN  R.  MOIII.KU.  chief;  HENRY  J.  WAHIIBTRN,  assistant 
chief. 

Quarantine  Division:  RICHARD  W.  HICKMAN,  chief. 
Division  of  Zoology-'  W.  H.  RANSOM,  chief. 

Erprriment  Station:  E.  C.  SCHROEDER,  Hiiperinteiulent;  W.  E.  COTTON,  assistant. 
Animal  Husbandman:  GEORCE  M.  ROMMEL. 
Editor:  JAMES  M.  PICKENS. 
Librarian:  BEATRICE  OBERLY  ROGERS. 

RIOCHEMIC   DIVISION. 

Chiff:  M.  Dorset. 

Assistant  chief:  James  A .  Emery. 

Meat  inspection  laboratories:  T.  M.  Price,  chemist  in  charge  of  central  lalxirat«>ry: 
A.  E.  Graham,  Ralph  Hoagland,  C.  H.  Swanger,  \Villiam  B.  Smith.  E.  A.  H<>\«r 
A.  H.  Roop.  Robert  M.  Chapin,  Clarence  T.  N.  Marsh,  Philip  Castleman,  E.  II.  IMI;«T 
soil,  W.  P.  Colvin.  assistant  chemists  in  branch  laboratories. 

/A-/  cholera  investigations:  In  charge  of  Chief  of  Division;  B.  M.  Bolton,  bacteri- 
ologist; C.  N.  McBryde,  bacteriologist;  W.  B.  Niles.  inspe<-tor  in  charge  of  licld 
experiments. 

Bacteriological  investigations  of  meat  food  products:  C.  N.  McBryde,  bacteriologist 
in  charge. 

Poultry  digestion  experiments:  E.  W.  Brown,  assistant  chemist  in  charge. 

Investigations  of  dips  and  disinfectants:  James  A.  Emery,  chemist;  C.  N.  McBryde, 
bacteriologist;  A.  M.  West,  assistant  bacteriologist. 

Preparation  of  tuberculin  and  mullein:  In  charge  of  Chief  of  Division;  A.  M. 
West  and  H.  J.  Shore,  assistant  bacteriologists;  \V.  S.  Stamper  and  II.  S.  McCauley. 
••fatanta. 

2 


LETTER  OF  TRANSMITTAL. 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY, 

Washington,  D.  C.,  April  12,  1907. 

SIR:  I  have  the  honor  to  transmit  herewith,  and  to  recommend 
for  publication  as  Bulletin  No.  100  of  this  Bureau,  a  paper  entitled 
"The  Germicidal  Value  of  Liquor  Cresolis  Compositus  (U.  S.  P.)," 
by  Dr.  C.  N.  McBryde,  bacteriologist  in  the  Biochemic  Division. 

The  substance  termed  "liquor  cresolis  compositus"  has  recently 
been  introduced  into  the  United  States  Pharmacopoeia,  and  the 
results  of  Doctor  McBryde' s  experiments  show  that  it  possesses  a 
germicidal  value  which  exceeds  that  of  carbolic  acid  for  the  bacteria 
upon  which  it  has  been  tested.  It  therefore  seems  that  this  solu- 
tion may  be  of  considerable  importance  as  a  disinfectant. 
Respectfully, 

A.  D.  MELVIN, 

Chief  of  Bureau. 
Hon.  JAMES  WILSON, 

Secretary  of  Agriculture. 

3 


CONTENTS. 


Pne-p. 

Introductory 7 

Standard  methods  of  testing  disinfectants 7 

The  drop  method 8 

The  rod  method 8 

Technique  of  present  experiments I 9 

Comparison  of  carbolic  acid  with  lime  and  carbolic-acid  mixture 9 

Comparison  of  carbolic  acid  with  liquor  cresolis  compositus  made  from  commer- 
cial cresols 11 

Comparative  value  of  solutions  of  liquor  cresolis  compositus  made  from  different 

cresols 14 

Separation  of  the  three  cresols  from  commercial  cresol 14 

Germicidal  value  of  liquor  cresolis  compositus  made  from  the  three  cresols.  15 
Comparison  of  carbolic  acid  with  liquor  cresolis  compositus  made  with  low- 
boiling  cresol 18 

Experiments  with  Bacillus  tuberculosis 20 

Experiments  with  Bacillus  anthraris 22 

Summary  of  results 24 

5 


THE  GERMICIDAL  VALUE  OF  LIQUOR  CRESOLIS 
COMPOSITUS  (U.  S.  P.). 


INTRODUCTORY. 

The  following  tests  were  undertaken  in  connection  with  the  ques- 
tion of  disinfecting  cattle  cars.  Heretofore  the  United  States  Depart- 
ment of  Agriculture  has  recommended  the  use  of  a  carbolic  acid  and 
lime  mixture  for  the  disinfection  of  cattle  cars,  pens,  chutes,  etc.  As 
there  were  certain  objections  to  the  use  of  this  mixture  it  seemed 
advisable  to  determine  whether  a  cheaper  and  more  efficient  disin- 
fectant could  not  be  found  for  this  purpose,  and  "liquor  cresolis  com- 
positus," which  has  been  recently  added  to  the  United  States  Phar- 
macopoeia, seemed  a  promising  substitute. 

Liquor  cresolis  compositus  is  a  liquid  soap  containing  50  per  cent 
of  cfesols,  which  have  been  shown  to  possess  high  disinfectant  prop- 
erties. It  is  a  thick,  dark  brown,  oily  looking  liquid  and  is  miscible 
with  water,  giving  clear,  saponaceous,  frothing  solutions. 

A  review  of  the  literature  on  disinfectants  fails  to  reveal  any  pre- 
vious tests  with  liquor  cresolis  compositus  (U.  S.  P.),  and  the  object 
of  the  tests  described  in  the  following  paper  was  to  determine  its 
efficiency  as  a  disinfectant  in  comparison  with  carbolic  acid,  which  is 
usually  adopted  as  a  standard  of  comparison  in  testing  disinfectants. 

In  testing  the  efficiency  of  a  disinfectant  the  ideal  method  would  be 
to  apply  the  tests  under  the  same  conditions  that  prevail  in  practice, 
according  to  the  purpose  for  which  the  disinfectant  is  to  be  employed. 
In  the  present  instance,  however,  where  the  object  in  view  was  the 
disinfection  of  cattle  cars,  chutes,  pens,  etc.,  this  would  have  been 
quite  impracticable  on  account  of  the  wide  variation  in  conditions 
which  would  be  met  with  in  practice,  and  it  was  therefore  deemed 
best  to  adopt  some  standard  method. 

STANDARD  METHODS  OF  TESTING  DISINFECTANTS. 

Of  the  various  methods  devised  for  testing  disinfectants,  the  best 
known  perhaps  are  the  "thread,"  the  "drop,"  the  "garnet,"  and  the 
"rod"  methods. 

In  a  recent  publication  °  the  disinfectant  standardization  committee 
of  the  Royal  Sanitary  Institute  of  London  reports  in  favor  of  the  drop 
method.  This  report  is  based  on  an  extensive  series  of  experiments 
conducted  by  Firth  arid  Macfadyen  to  determine  the  comparative 

"Journal  of  the  Royal  Sanitary  Institute,  Vol.  XXVII,  No.  1,  1906. 

7 


O1BMICIDAL    VALI'K    OF    LIQUO1    CTOBOLXI    COMP08ITU8. 

vjiluo  of  the  thread,  drop,  and  garnet  method*.  The  committee 
considered  the  drop  method  Miperior  to  both  the  thread  mid  'jarnet 
methods,  not  only  becau.se  of  its  simplicity  and  facility,  hut  because 
it  yielded  sharper  and  more  definite  iv-iilt».  Tin-  committee  con- 
sidered the  thread  method  too  elaborate  lor  general  u>e  and  •'emi- 
nently unfitted  for  working  with  mioTO-OIgailinili  at  all  sensitive  to 
desiccation." 

As  to  the  garnet  method,  the  committee  found  that  the  result- 
obtained  by  this  method  are  "too  irregular  to  justify  its  adoption 
as  a  means  of  obtaining  any  comparative  figure  of  disinfecting 
efficiency." 

In  the  following  paper  (lie  tesi^  were  made  according  to  the  drop 
and  rod  methods,  which  may  be  briefly  described  as  follows: 

I1IK   DROP  METHOD. 

This  is  one  of  the  simplest  and  most  widely  used  methods  of  testing 
disinfectants,  and  has  been  variously  modified.  The  drop  method 
employed  in  these  experiments  is  that  described  by  Ridcal  and 
Walker,0  and  is  the  one  which  was  adopted  by  the  British  standardi- 
zation committee,  referred  to  above,  as  the  most  satisfactory  method 
of  testing  disinfectants.  The  procedure  in  this  method  is  to  add  o 
drops  of  a  24-hour  culture  of  the  organism  upon  which  the  disinfectant 
is  to  be  tested,  grown  in  beef  broth,  to  5  c.  c.  of  the  disinfectant. 
The  mixture  is  then  well  shaken,  and  subcultures  are  made  from  it 
at  intervals  of  2\  minutes  up  to  15  minutes.  These  subcultures  arc 
then  incubated  at  38°  C.  for  at  least  2  days. 

THE    ROD    METHOD. 

This  method  was  devised  by  Hill  fc,  and  may  be  regarded  as  a 
convenient  modification  of  the  thread  method.  Glass  rods  th; 
sixteenths  of  an  inch  in  diameter  and  #  inches  long  are  etched  at 
one  end  with  diamond  ink.  Cotton  is  then  wrapped  about  the 
rods  near  one  end,  and  the  rods  are  thrust  into  test  tube*  ^»  a-  t» 
engage  the  cotton  in  the  mouth  of  the  tube.  The  tubes  containing 
the  rods  are  then  sterilized  by  dry  heat.  In  making  the  tests  the 
rods  are  removed  from  the  test  tubes  and  the  inclosed  or  etched 
portion  dipped  into  a  suspension  of  the  organism,  and  then  held  in 
the  air  for  a  few  moments  until  dry.  The  rods  are  then  transferred 
to  test  tubes  containing  5  c.  c.  each  of  the  disinfectant  to  be  tested  ;.nd 
ex|M>sed  to  the  action  of  the  disinfectant  for  varying  lengths  of  time. 
After  exposure  to  the  disinfectant  the  rods  are  dipped  in  sterile  water 
in  order  to  remove  all  traces  of  the  disinfectant  and  are  transferred 
to  tubes  of  sterile  beef  broth,  which  are  incubated  for  at  least  t  \voda\- 

0  Journal  of  the  Sanitary  Inotituto,  Vol   XXIV,  1908. 

6  Report  of  American  Public  Health  Amociatinn,  Vol.  XXIV,  1898. 


PRELIMINARY    COMPARISONS.  9 

at  38°  C.  The  suspension  of  the  organism  into  which  the  rods  are 
dipped  is  made  from  a  24-hour  culture,  grown  on  ordinary  neutral 
agar,  by  rubbing  up  in  several  cubic  centimeters  of  sterile  water 
enough  of  the  surface  growth  to  give  a  suspension  of  approximately 
the  same  density  as  a  24-hour  typhoid  culture. 

TECHNIQUE    OF   PRESENT   EXPERIMENTS. 

In  carrying  out  the  experiments  the  following  conditions  wore 
observed:  (1)  All  tests  with  disinfectants  were  made  at  room  tem- 
perature, which  was  duly  recorded  for  each  experiment.  (2)  The 
beef  broth,  prepared  from  freshly  chopped  meat  with  the  addition 
of  peptone  and  salt,  had  a  standard  reaction  of  1  per  cent  acid,  as 
recommended  by  the  American  Public  Health  Association.0  All 
tubes  of  beef  broth  contained  5  c.  c.  of  the  fluid.  (3)  All  subcultures, 
in  both  the  rod  and  drop  methods,  were  made  in  beef  broth,  and  were 
incubated  at  38°  C.  for  6  days,  except  where  growth  developed  earlier. 
(4)  In  the  drop  experiments  the  same  platinum  loop  was  used  for 
inoculating  the  subcultures.  (5)  Fresh  dilutions  of  the  disinfectants 
were  prepared  for  each  experiment  in  sterile  flasks  with  sterile  dis- 
tilled water. 

COMPARISON  OF  CARBOLIC  ACID  WITH  LIME  AND  CARBOLIC- 
ACID  MIXTURE. 

Before  proceeding  to  a  comparison  of  liquor  cresolis  compositus 
and  carbolic  acid  it  seemed  advisable  to  compare  the  lime  and  car- 
bolic-acid mixture  recommended  in  the  regulations  of  the  Secretary 
of  Agriculture6  for  the  disinfection  of  cattle  cars,  pens,  etc.,  with  car- 
bolic acid  alone,  in  order  to  determine  whether  the  addition  of  the 
lime,  which  was  added  to  the  carbolic  acid  solution  merely  for  the 
purpose  of  showing  where  the  latter  had  been  applied,  had  any  effect 
on  the  carbolic  acid ;  that  is,  whether  it  served  to  increase  or  dimin- 
ish its  germicidal  efficiency.  A  mixture  of  lime  and  carbolic  acid  was 
prepared,  therefore,  according  to  the  formula  given  in  the  aforesaid 
regulations.  This  formula  was  as  follows: 

Lime pounds. .     1J 

Carbolic  acid pound . .       ^ 

Water gallon . .     1 

In  making  up  this  mixture  for  the  tests  which  follow,  chemically 
pure  calcium  oxide  and  crystallized  carbolic  acid  c  were  used.  The 

°  Report  of  Committee  on  Standard  Methods  of  Water  Analysis  to  the  Lalx>ratory 
Section  of  the  American  Public  Health  Association,  Journal  of  Infectious  Diseases, 
Supplement  No.  1,  May,  1905. 

b  Regulations  of  the  Secretary  of  Agriculture  governing  the  inspection,  disinfec- 
tion, certification,  treatment,  handling,  and  method  and  manner  of  delivery  and  ship- 
ment of  live  stock  which  is  the  subject  of  interstate  commerce.  1905.  p.  9. 

c  In  this  and  all  of  the  following  tests,  crystallized  carbolic  acid  (U.  S.  P.)  was  used, 
31360-No.  100— 07 2 


10         UKKMKII'M      \    M.I    I'    "I 


UtKSnl.1-    .  <  -M  I'.  -  1  I  I   -. 


lime  was  weighed  in  a  sterile  Mask  and  a  sufficient  <|iiant  it  y  of  the 
water,  which  had  I  .....  n  previously  sterili/ed  l>y  hoiling,  was  addrd  i<> 
insure  thorough  slaking.  The  remainder  of  the  water  was  then  added, 
and  the  mixture  thoroughly  shaken  and  allowed  to  cool.  The  carholic 
acidcrvstaU  were  then  added,  and  the  mixture  wa>  >haken  well  and 
allowed  to  stand  for  several  hours  to  insure  complete  solution  of 
the  carholic  acid.  After  thorough  shaking,  portions  of  thi>  mixture 
\\cre  diluted  so  as  to  give  dilution-,  containing  carholic  acid  in  the 
proportion  of  1:100  and  1:125,  and  those  dilution-,  were  then  tested 
on  StapkylococciU  jryogenfs  avrrus  and  Bacillus  cholery  suis  in  com- 
parison with  aqueous  carholic-acid  solutions  of  equivalent  strength-. 
The  results  of  these  test*,  which  were  made  according  to  the  rod 
method,  are  shown  in  Tahles  1  and  '_'. 

TABI.K  1  .      '  '<>mpari»on  of  carbolic  arid  irith  mrboUr  arid  and  limr. 

|lt<xl  mi-tin..!.     orpnu*  n  i.  si.-.  I.  . 


iM  pyogrnr*  aureut,  24-hour  agarctilture  at  38°C.     Room 
temperature,  26°  to  27°  C.] 


Propor- 

Re«ilt  of 

exporarv  1 

o  dirinfect 

ant  for— 

I'isinf.vtMiit. 

CMrholic 

;ir|.|  in 
(lisinfwt- 
ant. 

2i  min- 
utes. 

.">  inin- 

atm, 

7JiPln- 

iii.-.. 

II  Miii  n- 

iil.--.. 

12)  in  i  n- 

.!.   ~. 

15  min- 
ute*. 

CMrlK>lio  ;irii|  mill  lituriiiixtiin- 
C»ri>ollc  »cid  »nd  water  

1:100 
1:100 

+ 
+ 

+ 
+ 

+ 
4. 

-»- 

+ 

+ 

+  means  growth;  -  means  no  growth. 
iTriiM-iilmNMl  for  6  days  at  38°  C. 

TABLE  2. — Companion  of  carbolic  acid  with  carbolic  arid  and  lime. 

[Rod  method.    Organism  tested.  Bacillu*  cholrrsr  nit,  24-hour  agar  culture  at  3H°  C.     Room  temper 

ture,  26°  to  27°  C.J 


Propor- 

Remiltof 

exposure! 

o  disinfect 

itnt  for 

Disinfectant. 

carl>ollc 
acid  in 
disinfect- 
ant. 

21  inin- 

lltl'H. 

5  min- 
utes. 

Tii.un- 

•ii.  -. 

10  min- 
utes. 

r.'i  min- 
utes. 

15  min- 
utes. 

Cartxilii-  ni-i.l  and  lime  mixture. 
C«rl«ilic  iK-jil  and  water  

1:126 
1:125 

+ 

+ 

- 

- 

- 

- 

+  means  growth:  -  means  no  growth. 
The  Milxniltures  wrre  Incubated  for  ft  days  at  33°  C. 

As  will  he  seen  from  Tahle  1.  the  carholic  acid  and  lime  mixture 
(carholic  acid  1:100)  failed  to  kill  N.  fnjogenes  aureu*  in  15  minute-. 
whereas  carholic  acid  alone  (1 :  100)  killed  in  10  minutes.  In  Tahle  _' 
we  see  that  it  required  an  exposure  of  7J  minutes  to  the  lime  and 
carholic  acid  mixture  (1 : 125)  to  kill  n.  cholfrx  «m,  whereas  an 
exposure  of  2)  minutes  to  carholic  acid  alone  (1:  125)  was  sufficient 
to  accomplish  the  same  result. 

It  will  thus  l>e  seen  that  the  addition  of  the  lime  to  the  carholic- 
acid  solution  materially  diminished  its  ^ennicidal  efficiency.  This 


CARBOLIC    ACID    AND    COMMERCIAL    CRESOLS.  11 

is  no  doubt  due. to  the  fact  that  part  of  the  carbolic  acid  combines 
with  the  lime  to  form  carbolate  of  calcium,  which  is  a  weaker  dis- 
infectant than  carbolic  acid. 

COMPARISON   OF   CARBOLIC   AGED  WITH   LIQUOR  CRESOLIS  COM- 
POSITUS  MADE  FROM  COMMERCIAL  CRESOLS. 

The  United  States  Pharmacopoeia  gives  the  following  directions 
for  the  preparation  of  liquor  cresolis  compositus: 

Grams. 

Cresol 500 

Linseed  oil 350 

Potassium  hydroxide 80 

Water,  a  sufficient  quantity  to  make 1, 000 

Dissolve  the  potassium  hydroxide  in  50  grams  of  water  in  a  tared  dish,  add  the 
linseed  oil,  and  mix  thoroughly.  Then  add  the  cresol  and  stir  until  a  clear  solution 
is  produced,  and  finally  sufficient  water  to  make  the  finished  product  weigh  1,000 
grams. 

Two  lots  of  liquor  cresolis  compositus  were  prepared  according  to 
the  above  formula  from  two  lots  of  cresol,  designated  hereafter  as 
Cresol  I  and  Cresol  II. 

These  cresols,  when  subjected  to  fractional  distillation  in  a  regula- 
tion Engel  flask,  gave  the  following  results: 

Cresol  I. — Fifty  grams  of  cresol  were  taken;  first  drop  distilled  at 
185°  C.;  the  temperature  rose  steadily  and  quite  rapidly  to  189°  C., 
then  slowly  to  190°  C.,  holding  for  some  time  between  190°  and  191°  C. 
The  fractional  distillation  of  this  cresol  gave  the  following  result : 

Below  187°  C 1.  60  per  cent.  This  fraction  was  colorless. 

From  187°  to  189°  C 2. 10  per  cent.            Do. 

From  189°  to  195°  C 70. 20  per  cent.            Do. 

From  195°  to  200°  C 17. 90  per  cent.  This  fraction  was  light  straw  in  color. 

From  200°  to  203°  C 4. 40  per  cent.  This  fraction  was  greenish  yellow  in 

color. 

Above  203°  C.  (by  difference) .  3. 80  per  cent.  This  fraction  was  dark  brown  in  color. 

100. 00  per  cent. 

Cresol  II. — Fifty  grams  of  cresol  were  taken;  first  drop  distilled  at 
185°  C. ;  the  temperature  then  rose  quite  rapidly  to  195°  C.,  then 
slowly  to  198°  C.,  holding  for  some  time  between  198°  and  199°  C. 
The  fractional  distillation  of  Cresol  II  was  as  follows: 

Water 1. 00  per  cent. 

Below  187°  C 1. 40  per  cent.  This  fraction  was  colorless. 

From  187°  to  189°  C 0.40  per  cent.            Do. 

From  189°  to  195°  C 1. 80  per  cent.            Do. 

From  195°  to  200°  C 80. 00  per  cent.            Do. 

From  200°  to  203°  C 14.  80  per  cent.  This  fraction  was  light  straw  in  color. 

Above  203°  C.  (by  difference).  0.  60  per  cent.  This  fraction  was  reddish  brown  in 

color. 


100. 00  per  cent. 


12         OKKMH  II»AI.    YAM   K 


CRKSoUS    r.>Mi'(1-l|i 


In  preparing  the  liquor  cresolis  compo^itus  made  uilh  <'re>nl  II, 
tin-  soapy  mixture  of  oil  and  hydrate  cleared  up  as  the  cresol  Mtf 
added.  l>iil  clouded  on  the  addition  of  the  last  |V\\  cubic  cenlimelei 
the  cresol:  on  the  addition  of  the  \\alrr.  however.  tin-  solution  became 
dear  a^'ain.  In  the  ease  of  the  liquor  c  resold  eompositus  made  with 
Cicxil  I,  the  mixture  of  oil  and  hydi.  me  clear  on  the  addition 

of  the  crexol.  I.  in  clouded  on  the  addition  of  the  water:  after  standing 
for  'J  I  hours.  however.  the  solution  hecanie  clear.  The  liquor  cresolis 
coinpositus  made  \\ith  (  'resol  II  was  slightly  darker  in  color  than 
that  inade  with  (Vesol  I.  In  making  dilutions  of  the  two  lots  of 
liquor  cre.xolis  coinpositus,  prepared  as  above.  it  was  found  that  the 
re>ull  int:  solutions  in  hoth  instance-,  \\ej-e  turbid.  A  5  per  cent 
dilution  of  liquor  cresolis  compositus  made  with  (  'resol  I  gave  an 
opaque,  milky  solution,  from  which  there  was  no  apparent  separation, 
while  a  similar  dilution  of  the  liquor  cresolis  compositus  made  with 
(Ye>ol  II  t,raYe  a  brownish,  turbid  solution,  from  which  there  was 
considerable  separatioiy  on  standing.  In  view  of  the  fact  that  there 
was  some  separation  in  the  case  of  the  liquor  cresolis  compositus  made 
with  (Vesol  II.  it  seemed  probable  that  saponilicat  ion  was  not  com- 
plete. so  portions  oi  this  preparation  were  heated  for  different  lengths 
of  time  oYer  a  steam  bath,  and  it  was  found  that  by  heating  for  one 
hour  complete  >aponifieat  ion  w  as  effected  and  perfectly  clear  solutions 
could  be  obtained  upon  dilution.  The  two  stock  solutions  of  liquor 
croolis  compositus  were  therefore  heated  for  one  hour  on  the  steam 
bath,  and  the  following  tests  were  made  with  these  solutions: 

TABI.K  3.-  -Comjiaruon  of  carbolic  acid  with  lii/nor  crtsolit  ro//i/>o*i'/i/.<r  mmlf  from  com- 

iin  n-ial  cresols. 

Drop  ini-ihixl.    Orgnnisiii  t.-sti-.l.  fiiiii>hytororrui  pyoffene*  amrrut.  24-hour  broth  culturp  at  38°  C. 

Room  t.'mp.Titture2fi°C.) 


Strcngth 

I;.  Mill  nl 

oxposum 

1..  .liMnf.x- 

tnnt  for— 

.:if«-tant. 

5 

soliltinii. 

2)  niin- 
iii.  >. 

5  min- 
ute*. 

7)  min- 
ute*. 

10  iinii- 
\ite*. 

12    :  lii  - 
ute*. 

15min- 

UtM. 

CarlMilicarid.  . 

1:80 

1   Hi) 

4- 

4 

4 

4 

_ 

_ 

Do  

1   l.'.'i 

4- 

4 

4 

4. 

4 

4- 

l.iiiuor     <TCH«|IS     i-nuiiM>!i|tu* 

1:125 

4. 

4 

4 

I.iciiii.r     rf«u.|i-i     i-oiiiixi-ilii- 

1:125 

4. 

4 

4  nw-atw  growth:  —  iwnnx  no  growth. 
TN-  <«til>riilt  .  nhiitfil  for  «  iUy»  at  38°  C. 

Car»K>lK--iu-i  :  •!,<•  componituii  made  with  Cn-nol  1-1.40. 

Carbolic-acid  ooefllcicnt  of  liquor  r rraolis  oompoaltu*  nuuln  with  Croaol  II-  l.«M-. 


CARBOLTC    ACID    AND    COMMERCIAL    CRESOLS. 


13 


TABLE  4.— Comparison  of  carbolic  acid  with  liquor  cresolis  compositus  made  from  com- 
mercial cresols. 

[Drop  method.    Bacillus  pyocyaneus,  24-hour  broth  culture  at  38°  C.    Room  temperature,  26°  C.J 


Disinfectant. 

Strength 
of  solu- 
tion. 

Result  of  exposure  to  disinfectant  for— 

2J  min- 
utes. 

5  min- 
utes. 

?i  min- 
utes. 

10  min- 
utes. 

12J  min- 
utes. 

15  min- 
utes. 

Carbolic  acid 

1:125 
1:135 
1:200 

1:200 
1:200 

+ 
+ 

+ 
+ 

+ 

+ 

+ 

+ 

+ 
+ 

+ 

+ 

+ 

+ 

Do 

Do        

Liquor     cresolis     compositus 
(Cresol  1) 

Liquor     cresolis     compositus 
(Cresol  II)                  

+  means  growth;  —  means  no  growth. 
The  subcultures  were  incubated  for  6  days  at  38°  C. 

Carbolic-acid  coefficient  of  liquor  cresolis  compositus  made  with  Cresol  1=1.48. 
Carbolic-acid  coefficient  of  liquor  cresolis  compositus  made  with  Cresol  11=1.54  (average  of  1.48  and 
1.60). 

TABLE  5. — Comparison  of  carbolic  acid  with  liquor  cresolis  compositus  made  from  com- 
mercial cresols. 

Drop  method.    Bacillus  cholerx  suis,  24-hour  beef-broth  culture  at  38°  C.     Room  temperature,  26°  C.] 


Disinfectant. 

Strength 
of  solu- 
tion. 

Result  of  exposure  to  disinfectant  for  — 

2J  min- 
utes. 

5  min- 
utes. 

7J  min- 
utes. 

10  min- 
utes. 

12J  min- 
utes. 

15  min- 
utes. 

Carbolic  acid  

1:125 
1:135 
1:200 

1:200 
1:200 

+ 
+ 

+ 
+ 

+ 
+ 

+ 

+ 

+ 

+ 

+ 

Do  

Do  

Liquor     cresolis    compositus 
(Cresol  I)  

Liquor    cresolis    compositus 
(Cresol  II)  

+  means  growth;  —  means  no  growth. 

The  subcultures  were  incubated  for  6  days  at  38°  C. 

Carbolic-acid  coefficient  of  liquor  cresolis  compositus  made  with  Cresol  1=1.54  (average  of  1.48  and 
1.00). 

Carbolic-acid  coefficient  of  liquor  cresolis  compositus  made  with  Cresol  11=1.54  (average  of  1.48  and 
1.60). 

The  carbolic-acid  coefficients  in  Tables  3  to  5  are  obtained  as  fol- 
lows: A.  dilution  of  carbolic  acid  is  first  obtained  which  kills  the 
organism  within  a  given  time;  a  dilution  of  the  disinfectant  is  next 
obtained  which  kills  the  organism  in  the  same  time  as  the  carbolic- 
acid  dilution;  the  dilution  of  the  disinfectant  divided  by  the  carbolic- 
acid  dilution  gives  a  ratio  which  is  called  the  carbolic-acid  coefficient. 
This  coefficient  represents  the  efficiency  of  the  disinfectant  expressed 
in  multiples  of  carbolic  acid  performing  the  same  work. 

Taking  an  average  of  the  carbolic-acid  coefficients  in  the  above 
tables  we  find  that  for  the  three  organisms  tested  the  two  solutions  of 
liquor  cresolis  compositus  made  from  commercial  cresols  are  approxi- 
mately one  and  one-half  times  more  efficient  than  carbolic  acid.  We 
also  find  that  the  solution  of  liquor  cresolis  compositus  made  with 
Cresol  II  is  slightly  more  efficient  than  that  made  with  Cresol  I, 
which  may  be  explained  by  the  fact  that  Cresol  II  contains  a  higher 
percentage  of  the  high  boiling  cresols,  it  being  generally  conceded 


14        GKICMIt  ii. M.    VM.UK   OP   LK»i..K    ORB8OLI8   COMPO8ITU8. 

by  must  investigators  that  the  higher  l>i.iliii-_r  en-sols,  i.  e.,  para- 
cn-sol  ami  metacn-sol,  an-  more  efficient  disinfectants  than  orthoci. 

In  an  investigation  of  the  en-sol  soaps  of  ( icnnan  comnierce  l-'ehr-  " 
found  that  en-sol  soaps  containing  the  same  amount  of  crude  eiesol 
varied  in  disinfectant  ellieiency.  and  he  attributed  this  variation  to 
differences  in  the  chemical  compositit>n  of  the  crude  cn-so!-,  from  which 
the  soaps  \\ere  made:  tliat  is,  to  differences  in  the  relative  amounts 
of  orthoeresol,  paraeresol,  and  metacresol  eontnined  in  these  en-sols. 
In  the  course  of  his  investigation  Fehrs  found  that  paraeresol  and 
metacresol  were  both  more  active  disinfectants  than  oi  t  hoc-re-,  ,1. 
and  ho  explains  the  varying  disinfectant  values  of  the  cn^ol  soap-.  <>n 
this  Around. 

-  'inewhat  at  variance  with  these  results,  however,  are  the  more 
recent  experiments  of  Schneider/'  who  prepared  a  -cries  ,.!'  <•[<•-. .1 
soaps  containing  e<jual  ninounts  of  orthoeresol.  paraeresol.  and  meta- 
cresol, and  found  the  m«-tacresol  preparation  to  be  the  most  efficient. 
but  could  discover  no  difference  in  the  disinfectant  efficiency  of  the 
orthoeresol  and  paracresol  preparations. 

In  view  of  these  somewhat  conflicting  results  the  following  te-ts 
were  made: 

COMPARATIVE    VALUE     OF     SOLUTIONS     OF     LIQUOR     CRESOLIS 
COMPOSITUS    MADE    FROM    DIFFERENT    CRESOLS. 

SEPARATION    OF    THE    THREE    CKKSO1.S    KKOM    ( '<  >M  \l  KIM  I  \l.    <  IM'.SOL. 

Cresol  II,  which  contained  less  than  1  per  cent  of  impurities  in  the 
form  of  tar  oils  and  bases,  was  used  for  this  work  and  was  purified  in 
the  following  manner:  Five  hundred  cubic  centimeters  of  the  en-sol 
was  shaken  in  a  separatory  funnel  with  sulphuric-acid  solution  (1:3) 
and  allowed  to  stand  until  complete  separation  into  layers  had  taken 
place.  The  lower  (aqueous)  layer,  containing  a  sulphuric-acid  extract 
of  "organic  bases,"  was  then  removed.  Tin-  residue  was  next  made 
alkaline  with  25  per  cent  sodium-hydrate  solution.  Ether  was  then 
added,  and  the  mixture  was  thoroughly  agitated  and  allowed  to  stand 
over  ni^ht  to  separate.  The  lower  layer,  containing  the  tar  acids 
(phenols,  cresols,  etc.)  in  solution  in  soda  as  phenylates.  en-sylates. 
etc..  was  separated  from  the  upper  (ethereal  layer  containing  any  tar 
oils  present.  The  solution  of  tar  acids  in  soda  was  then  made  acid 
by  adding  an  excess  of  sulphuric  acid  '1:3)  and  allowed  to  cool;  it 
was  then  agitated  with  ether  several  times  until  all  liberated  tar  acids 
were  extracted.  The  ether  was  driven  off  from  this  extract  by  gentle 
heating  on  a  steam  bath,  and  the  residue  of  tar  acids  thus  obtained 
was  placed  in  a  distillation  flask  and  subjected  to  careful  fractional 
distillation.  The  distillation  was  repeated  three  times,  and  three 
fractions  approximating  orthoeresol.  paracresol,  and  metacresol  were 

"CVntralM.  fur  Bakt.,  Paraait.  und  Infectioiwkr. ,  Bd.  XXXVII,  Abt.  I,  1904. 
*Zeit.  far  Hyg.  und  Infectionskr.,  Bd.,  53,  1906. 


COMPARISON    OF    SOLUTIONS    MADE    FROM    DIFFERENT    CRESOLS.     15 


collected,  as  follows:  (1)  A  fraction  which  distilled  over  constantly 
between  187°  and  189°  C.  (2)  A  fraction  which  came  over  constantly 
between  195°  and  199°  C.  (3)  A  fraction  which  came  over  con- 
stantly between  200°  and  203°  C. 

The  boiling  points  of  the  three  cresols  are  usually  given  as  follows : 
Orthocresol,  188°  C.;  paracresol,  198°  C.;  metacresol,  201°  C.  There 
is,  however,  considerable  variation  in  the  boiling  points  of  the  three 
cresols  as  recorded  by  different  observers,  and  because  of  this  varia- 
tion the  fractions  were  collected  within  the  limits  stated  above. 

GERMICIDAL  VALUE   or   LIQUOR  CRESOLIS   COMPOSITUS  MADE  FROM 

THE    THREE    CRESOLS. 

Solutions  were  prepared  from  each  of  the  three  fractions  described 
in  the  preceding  paragraph,  according  to  the  formula  of  the  United 
States  Pharmacopoeia  for  liquor  cresolis  compositus,  and  the  tests 
which  follow  were  made  with  dilutions  from  these  solutions.  The 
stock  solutions  in  this  instance,  as  in  the  case  of  liquor  cresolis  com- 
positus prepared  from  the  commercial  cresols,  were  heated  for  one 
hour  on  a  steam  bath,  in  order  to  insure  complete  saponification. 

In  the  following  tests  a  comparison  was  made  of  the  drop  and  rod 
methods  in  addition  to  the  comparison  of  the  germicidal  value  of 
the  different  cresols : 

TABLE  6. —  Comparison  of  solutions  of  liquor  cresolis  compositus  made  from  cresols  which 
boil  at  temperatures  approximating  orthocresol,  paracresol,  and  metacresol. 

[Drop  method.    Organism  tested,  Bacillus  typhosus,  24-hour  beef-broth  culture  at  38°  C.    Room 

temperature,  30°  C.] 


Disinfectant. 

Strength 
of 
solution. 

Result  of  exposure  to  disinfectant  for  — 

2J  min- 
utes. 

5  min- 
utes. 

7J  min- 
utes. 

10  min- 
utes. 

12J  min- 
utes. 

15  min- 
utes'. 

Liquor     cresolis     compositus 
containing  — 
Cresol  187°  to  189°  C 

1:350 
1:350 
1:350 

4- 

+ 
4- 

+ 
4- 

+ 
4- 

4- 
4- 

+ 

+ 

Cresol  195°  to  199°  C.  . 

Cresol  200°  to  203°  C  

+  means  growth;  —  means  no  growth. 

The  subcultures  were  incubated  for  6  days  at  38°  C. 

• 

TABLE  7. — Comparison  of  solutions  of  liquor  cresolis  compositus  made  from  cresols  which 
boil  at  temperatures  approximating  orthocresol,  paracresol,  and  metacresol. 

[Kod  method.    Organism  tested,  Bacillus  typhosus,  24-hour  asar  culture  at  38°  C.    Room  temperature, 

28°  C.] 


Disinfectant. 

Strength 
of 
solution. 

Result  of  exposure  to  disinfectant  for— 

2J  min- 
utes. 

5  min- 
utes. 

7J  min- 
utes. 

10  min- 
utes. 

12J  min- 
utes. 

15  min- 
utes. 

laquor    cresolis     compositus 
containing— 
Crcsol  187°  to  189°  r  

1:450 
]:450 
1:450 

+ 
+ 
4- 

4- 
+ 

4- 
4- 

4- 

4- 

4- 

Cresol  195°  to  199°  C 

Cresol  200°  to  203°  C  

4-  means  growth;  —  means  no  growth. 
The  subcultures  were  incubated  for  6  days  at  38°  C. 


Ill         i.l  KMI'  IDAL    VAI.TK    «>[-     l.UjfnK    riM->« 'I.I- 


TMUK    S        '  .. ;;./»•!/  -w«»n  njunlulintu  <>/'/i</  •  rni/i/mai/  .;/(  crcKtilx 

boil  at  lint  i*  ratlins  d/i/in»i  iinntiiui  art  tun-mini .  y«/n/<v.  .to/.  <i;i</  //i»/n. 

[l>r.«|i  mi-tiiixi.     organUni  tmti*<l.  Siniihi/locoenu  pyogenet  attrnu.  24-hour  !•••«•(  l.roth  <  tiltuns  itt  38*  C 

Room  temperature.  2V  C.) 


Slr.-i.Ktl. 

i;.  MU  ..( 

.  -\lMisiir.- 

ii  'IMiifii- 

hint  (or 

:-if.vUnt. 

3 

Mlllltioll 

."  mln- 

.Mull 

7J  inln- 

10  tlllll- 

IJJ  mitt- 

15  mln- 

l.i<|in«r     i-p-Milii     <  otiipoaltua 
containing 
Cn-xol  IN7e  to  IH»°  C  

1:250 

4- 

4. 

+ 

. 

4. 

Crvsol  111'.0  to  199°  ('  

I:2fiO 

4. 

+ 

_ 

Crvsol  300°  to  203°  C  

1:2.10 

4- 

4- means  growth;       nmin*  n< 
ii«  iiltnrvs  wrrv  in.  iii. Mt. ••!  (or  6  days  at  XV  ('. 


T  v  in  h    '.I       I  'tiiiii>iirixnn  of  solutions  of  /u/i/or  i-rmnlis  .>»//!  /KMI/I/.V  ;//W/  /Vf/m  rrc*ol*  which 
boil  at  ti  in  i>i  rat  tins  ni>i>ro.iiinal\nii  nrthwrrmd.  /niriii-ri  snl .  nml  nu  turn  mil. 

|K.»I  inrtlKMl.     Organism  t.'.sl.-il,  >'/«/)Aj//ororru*  )>yogrnr*avrru*.  '-M-hoiir  HKHT  i-iiltun-  »t  :w°C.     It. HIM. 

°   ' 


Disinf.'.  tiii.t. 

StrcnKth 
of 

snliition. 

.".  niii; 
»      UU>8. 

.'.  linn 

ul.-- 

7)  min- 

iii<-. 

10  min- 
utes. 

r.'j  m  ii- 
nti  - 

1.'.  Illlll 

utea. 

Litpior     «TP»oli«     coin  posit  uii 
containing 
Cre«)l  187°  to  189°  C  . 

1:300 

4. 

4. 

4- 

4- 

4. 

4. 

(  n-»ol  l{tt°tolW°C  
Civftol  200°  to  303°  C  

I   .tm 
1:300 

4- 

4-  means  growth;  —  means  no  growth. 
Thp  MiU-ultiin>s  wrro  iiK-uhaUni  for  6  days  at  38°  C. 


TABLE  10. — Comparuonof  solutions  of  liquor  crrsoli*  com  poxit  us  made  from  rretoln  uhirh 
boil  at  temperatures  approximating  orthorresol,  paracretol.  and  metarresol. 

[Drop  method.    Organism  tested,  Baritiu*  coli  communi*.  24-hour  N-.-f  i.n.ih  niltunc  at  38°  C.     Room 

trmpi>rature,  28°  C.] 


Strength 

Rcaultof 

expostiiv 

to  diainfec 

tant  for— 

Dialnfei-tant. 

oT 
solution. 

2)  min- 
utes. 

.".  nun 
utes. 

7)  in  n 
utes. 

10  min- 
utes 

l.'i  min- 
utes. 

15  111:11- 

•.i.  - 

Liquor    cresolia    composltiis 
containing 
"1  187°  to  1W°  C  

1:250 

4- 

4- 

4- 

4- 

4- 

• 

Cnwol  1K°  to  198°  C 

1   j.-Ji 

4. 

4- 

4- 

4. 

Crvsol200°  to  203°  C.'  

1:250 

4. 

4- 

_ 

_ 

4-  means  growth:  —  moans  no  growth. 
The  iu>M:ultures  w.-rv  in.  ut>nU-<l  for  6  days  at  38°  C. 

TAHI.K  1 1 . — Compariton  of  solutions  of  liquor  rrnuilin  rompotitu*  matiefrom  rrtaol*  which 
boil  at  temperatures  ai>iiro.iiituitiny  vrthocresol,  paracnxol.  nml  >iutn< 

|  H«»l  iix-t h<»l.     <  irganism  tested,  Bacillus  coli  comiimni*.  24-hour  agar  culturr  at  38°  C.     Room  t«-in i-  r 

atuir.  31°  C  ] 


Strength 

Result  of  exposure 

tant  (or 

Disinfectant. 

of* 
•oiution. 

2J  min- 

;:!  — 

.'.mm-       7J  min- 
utes,         utes. 

10  in-  n- 
utes. 

12)  m  n-     I.S  min- 
utes,         utes. 

Uquor     CTMolls     rotnpoaitus 

.nine 
-:"  to  IHB»C  

1:300 

4- 

4- 

4- 

. 

'o|  HKi»  to  !«>•('  

1  300 

4. 

4.                     — 

«ol  200*  to  200*  C  

1:300 

4. 

_ 

_               _ 

1 

4-  means  growth;  -  mean*  no  growth. 
The  subcultures  were  incubated  for  0  days  at  38*  C. 


COMPARISON    OF    SOLUTIONS    MADE    FROM    DIFFERENT    CRESOLS.     17 


TABLE  12. — Comparison  of  solutions  of  liquor  cresolis  compositus  made  from  cresols  which 
boil  at  temperatures  approximating  orthocresol,  paracresol,  and  metacresol. 

[Drop  method.    Organis.n  tested,  Bacillus  pyocyaneus,  24-hour  beef-broth  culture  at  38°  C.    Roo.:i 

t<>  uperature,  31°  C.] 


Disinfectant. 

Strength 
of 
solution. 

Result  of  exposure,  to  disinfectant  for  — 

2*  min- 
utes. 

5  min- 
utes. 

7J  min- 
utes. 

10  min- 
utes. 

12.J  min- 
utes. 

15  min- 
utes. 

Liquor     cresolis     compositus 
containing  — 
Cresol,  187°  to  189°  C  

1:300 
1:300 
1:300 

+ 
+ 
+ 

+ 

+ 

+ 

+ 

+ 

«f 

Cresol,  195°  to  199°  C 

Cresol,  200°  to  203°  C  

+  means  growth;  —  means  no  growth. 
The  sulxjultures  were  incubated  for  6  days  at  38°  C. 

TABLE  13. — Comparison  of  solutions  of  liquor  cresolis  compositus  made  from  cresols  which 
boil  at  temperatures  approximating  orthocresol,  paracresol,  and  metacresol. 

[Rod  method.    Organism  tested,  Bacillus  pyocyaneus,  24-hour  agar  culture  at  38°  C.    Room  tempera- 
ture, 29°  C.] 


Disinfectant. 

Strength 
of 
solution. 

Result  of  exposure  to  disinfectant  for— 

2J  min- 
utes. 

5  min- 
utes. 

7J  min- 
utes. 

10  min- 
utes. 

12J  min- 
utes. 

15  min- 
utes. 

Liquor  cresol  compositus  con- 
taining— 
Cresol,  187°  to  189°  C 

1:300 
1:300 
1:300 

+ 
+ 
+ 

+ 
+ 
+ 

+ 
+ 

+ 

+ 

+ 

Cresol,  195°  to  199°  C  
Cresol,  200°  to  203°  C 

+  means  growth;  —  means  no  growth. 
The  subcultures  were  incubated  for  6  days  at  38°  C. 

From  Tables  6  to  13  it  will  be  seen  that  the  germicidal  efficiency 
of  liquor  cresolis  compositus  increases  with  the  boiling  point  of  the 
cresol  it  contains.  It  will  also  be  noted  that  the  two  solutions  of 
liquor  cresolis  compositus  made  from  the  two  higher-boiling  cresols 
(i.  e.,  those  approximating  paracresol  and  metacresol)  are  both  very 
much  more  efficient  and  stand  apart,  as  it  were,  from  the  solution 
made  from  the  lowest-boiling  cresol,  which  approximates  orthocresol. 

In  comparing  the  results  obtained  by  the  drop  and  rod  methods 
we  find  that  as  a  rule  the  organisms  tested  were  more  easily  killed  on 
the  rods.  By  the  rod  method  Bacillus  typhosus,  B.  coli  communis, 
and  Staphylococcus  pyogenes  aureus  were  killed  by  more  dilute  solu- 
tions than  were  required  by  the  drop  method,  and  it  would  seem 
probable  that  the  resistance  of  these  organisms  was  somewhat  low- 
ered by  the  drying  to  which  they  were  subjected  in  the  rod  method. 
B.  pyocyaneus  was  killed  by  the  same  strength  of  solutions  in  prac- 
tically the  same  length  of  tune  with  both  methods,  and  it  would 
seem  that  this  organism  was  probably  more  resistant  to  desiccation 
than  the  ones  mentioned  above.  From  these  results  it  would  seem 
that  the  same  objection  that  Firth  and  MacFadyen  found  to  the 
thread  method  would  hold  for  the  rod  method — i.  e.,  that  it  is  not 
well  fitted  for  working  with  organisms  that  are  sensitive  to  desiccation. 


18        OKKMlUlt.M.    VALUE   OK   LIQUOR   CRr>"l .1- 


COMPARISON  OF   CARBOLIC  ACID   WITH  LIQUOR   CRE8OLIS   COM- 
POSITUS  MADE  WITH   LOW-BOILING  CRESOL. 


In  the  preceding  >e<-ti<>n  it  \\as  round  that  li<|iior  cre^.lU  com- 
pos it  us  made  with  a  creM>l  which  lioiLs  at  a  temperature  approxi- 
mating orthocre-.>l  i.  «•..  1S7°  to  189°  C.)  was  much  the  weakest 
disinfectant  of  three  preparations  made  from  a  series  of  cresols 
approximating  orthocresol,  paracresol,  and  metacresol.  In  the 
following  tahles  this  solution  of  li(pi<ir  cresolis  compo>itus.  which  was 
made  from  the  lowest-hoiling  cresol  of  tlie  scries  and  foil  ml  to  he  the 
weakest  of  the  three  preparations  in  gcrmicidal  value,  is  compared 
with  carbolic  acid: 


TABLE  14.  —  Comjiari*on  of  carbolic  acid  uith  /i'//i/or  craolu  compontm  (cretol  187°  to 

189°  ('  .  i. 

II>rop  nirthrxl.     organism  tested.  Rarillu*  coli  communi*.  24-hour  liccf-broth  culture  at  38*  C.    Room 

tenpermture.  24°  to  28°  C.] 


DMnfccUnt. 

Strpngth 
of 
solution. 

Result  of  exposure  to  dlninfrvtant  for— 

2J  min- 
utes. 

5  min- 
ute*. 

7J  min- 

•n. 

10  min- 
utea. 

12}  rnln- 
nu». 

!.'•  min- 

Liquor    crpaolis    compositus 
(oreaol  1S7°  to  189°  C.)  

1:175 
1:175 
1:125 
1:100 

+ 
+ 
+ 

+ 
+ 
+ 

+ 
+ 

+ 
+ 

+ 
+ 

+ 
+ 

»'ltrl>»llr  lii'l'l 

Do... 

Do  

+  ipeans  growth;  -  means  no  growth. 

• 

The  subcultures  were  inculmted  for  6  days  at  38°  C. 
Carbolic-acid  coefficient  -  1.67  (average  of  1.40  ami  1.75). 

TABLE  15. — Companion  of  carbolic  acid  rnth  liquor  cre»ol\»  compositnt  (cretol  187°  to 

189°  C.). 

[Dmp  method.    Organism  tested.  Bacillus  typh&tut.  24-hour  beef-broth  culture.    Room  temperature, 

2>to  30»  C.] 


Strength 

Result  of 

expoHtire 

to  dirinfecUnt  for— 

l»i-inf.rtiiTit. 

of 
solution. 

•-M  mln- 
••:•  | 

Smln- 

•.:.  - 

;    n  h  - 
utes. 

lOmin-      I?J  min- 
utes,         utes.  • 

I.",  min- 
utes. 

Liquor     CresolU     rnmpositus 
(crmol  187°  to  18»°  P.)  

1:200 

+ 

+ 

(«rt«,  lie  acid... 

1:200 

+ 

+ 

-f 

+                + 

4. 

Do  

1:135 

+ 

+ 

4. 

Do  

1:125 

4. 

—        1  •      «• 

—  . 

4-  means  growth:  -  means  no  growth. 

The  subcultures  were  Incubated  for  fi  days  at  38°  C. 
Carbolic-Mid  coefficient  -  1.54  (average  of  1.48  and  1.00). 


CARBOLIC    ACID    AND    LOW-BOILING    CRESOL. 


19 


TABLE  16. — Comparison  of  carbolic  acid  with  liquor  cresolis  compositus  (cresol  187°  to 

189°  C.). 

[Drop  method.    Organism  tested,  Bacillus  cholerx  suis,  24-hour  beef-broth  culture  at  38°  C.    Room 

temperature,  26°  C.] 


Disinfectant. 

Strength 
of 
solution. 

•  Result  of  exposure  to  disinfectant  for— 

2J  min- 
utes. 

5  min- 
utes. 

7J  min- 
utes. 

10  min- 
utes. 

12J  min- 
utes. 

15  min- 
utes. 

Liquor     cresolis     compositus 
(cresol  187°  to  189°  C  ) 

1:175 
1:175 
1:135 
1:125 

+ 

+ 
+ 

+ 
+ 
+     . 

+ 
+ 

+ 

+ 

+ 

Carbolic  acid 

Do...             

Do  

+  means  growth;  —  means  no  growth. 
The  subcultures  were  incubated  for  6  days  at  38°  C. 
Carbolic-acid  coefficient  =  1.35  (average  of  1.30  and  1.40). 

TABLE  17. — Comparison  of  carbolic  acid  with  liquor  cresolis  compositus  (cresol  187°  to 

189°  C.). 

[Drop  method.    Organism  tested,  Bacillus  pyocyaneus,  24-hour  beef-broth  culture  at  38°  C.    Room 

temperature,  27°  C.] 


Disinfectant. 

Strength 
of 
solution. 

Result  of  exposure  to  disinfectant  for  — 

2J  min- 
utes. 

5  min- 
utes. 

7J  min- 
utes. 

10  min- 
utes. 

12J  min- 
utes. 

15  min- 
utes. 

Liquor     cresolis     compositus 
(cresol  187°  to  189°  C.) 

1:175 
1:175 
1:150 
1:135 

+ 

+ 
+ 
+ 
• 

+ 
| 

+ 
+ 
+ 
+ 

+ 

+ 
+ 

+ 
+ 

+ 
+ 

Carbolic  acid.             

Do 

Do... 

+  means  growth;  -  means  no  growth. 
The  subcultures  were  incubated  for  6  days  at  38°  C. 
Carbolic-acid  coefficient  =  1.23  (average  of  1.30  and  1.16). 

TABLE  18.  —  Comparison  of  carbolic  acid  with  liquor  cresolis  compositus  (cresol  187°  to 

189°  C.. 


[Drop  method.    Organism  tested,  Staphylococcus  pyogenes  aureus, 

temperature,  27°  to  30°  C.] 


24-hour  beef-broth  culture.    Room 


Disinfectant. 

Strength 
of 
solution. 

Result  of  exposure  to  disinfectant  for  — 

2J  min- 
utes. 

5  min- 
utes. 

1\  min- 
utes. 

10  min- 
utes. 

121  min-, 
utes. 

15  min- 
utes. 

Liquor     cresolis     compositus 
(cresol  187°  to  189°  C.)  

1:  150 

1:  150 
1:  100 
1:  80 

+ 
+ 
+ 

+ 
+ 

+ 
+ 

+ 
+ 

+ 

+ 

Carbolic  acid 

Do  

Do  

+  means  growth;  —  means  no  growth. 
The  subcultures  were  incubated  for  6  days  at  38"1  C. 
Carbolic-acid  coefficient =1.63  (average  of  1.50  and  1.87). 


20         OK.UMlt  il».\l.    VAI.I'K    OK    UijroK    CKKSoUrt    OOMPO8ITU8. 

Talking  an  average  of  tin*  carbolic-acid  coefficients  in  Tables  I  I  Is, 
it  will  be  found  I  lint  for  the  I'm*  organisms  tested  the  gcrmicidal  elli- 
ciency  «>f  liquor  cresolis  composing  made  \vitli  cre^.l  which  boils 
between  1S7°  and  ivi  ('.  is  nearly  one  and  one-half  times  greater 
than  that  of  carbolic  acid. 

\Vc  thus  s<><>  that  a  solution  of  liquor  cresolis  compositus  made  from 
the  lowest-boiling  and  least  effective  cresol  (i.  e.,  cresol  187°  to  189° C.) 
has  a  higher  disinfectant  value  than  carbolic  acid,  and  we  may  safely 
conclude,  therefore,  that  a  solution  of  liquor  cresolis  compositus  made 
from  any  cresol  \\hieh  boils  at  the  temperatures  specified  by  the 
United  States  IMiarmacopu-ia  ( !'.»">  to  -J05°  G.)  would  surpass  carbolic 
acid  in  disinfectant  eflieiency. 

EXPERIMENTS  WITH  BACILLUS  TUBERCULOSIS. 

A  culture  of  Bacilhift  tubfrmlozis  grown  at  38°  C.  on  beef  broth  con- 
taining peptone,  glycerin,  and  acid  potassium  phosphate  was  selected 
for  this  experiment.  The  culture  was  17  days  old,  and  showed  a 
well-developed  pellicle  covering  the  entire  surface.  Several  bits  of 
the  growth  were  removed  by  means  of  a  platinum  loop,  placed  in  the 
bottom  of  a  dry,  sterile  test  tube,  and  thoroughly  macerated  by  means 
of  a  heavy  platinum  rod 'flattened  at  the  end.  Three  cubic  centi- 
meters of  normal  salt  solution  was  then  added,  and  some  bits  of 
sterile  glass,  and  the  tube  was  thoroughly  agitated.  The  tube  was 
then  allowed  to  stand  for  about  half  an  hour,  at  the  end  of  which  time 
the  coarser  particles  had  settled  out,  leaving  a  homogeneous  sus- 
pension of  about  the  density  of  a  48-hour  typhoid  culture.  This  sus- 
pension was  carefully  drawn  off  by  means  of  a  sterile  pipette,  and 
transferred  to  a  dry,  sterile  test  tube.  Sterile  glass  rods  with  etched 
ends  (Hill's  method)  were  then  dipped  in  this  suspension,  and  allowed 
to  dry  for  a  few  moments  in  the  air.  The  rods  were  then  exposed  for 
varying  intervals  of  time  to  1  per  cent  solutions  of  carbolic  acid  and 
liquor  cresolis  compositus  (cresol  187°  to  189°  C.).  After  exposure 
to  the  antiseptic  each  rod  was  dipped  in  a  large  test  tube  containing 
50  c.  c.  of  sterile  water  in  order  to  get  rid  of  all  traces  of  the  disin- 
fectant and  the  bacilli  were  then  carefully  washed  from  the  rods 
in  2  c.  c.  of  sterile  salt  solution  in  a  small  sterile  beaker.  A  small 
glass  rod,  tipped  with  rubber  tubing  and  sterilized  by  boiling,  was 
used  in  washing  the  tubercle  bacilli  from  the  end  of  the  etched  rod, 
the  latter  being  thoroughly  nibbed  in  the  salt  solution  with  the  rubber- 
tippet!  rod,  so  as  to  remove  all  of  the  tubercle  bacilli  adhering  to  the 
etched  portion.  The  salt  solution  containing  the  tubercle  bacilli 
which  had  been  exposed  to  the  action  of  the  disinfectant  was  then 
injected  into  n  guinea  pig  beneath  the  skin  of  the  flank.  Guinea  pigs 
were  also  inoculated  from  check  rods  which  had  received  a  film  of 
bacilli  and  had  then  been  dipped  in  sterile  water  and  washed  off  in 


EXPERIMENTS    WITH    BACILLUS    TUBERCULOSIS. 


21 


salt  solution  in  the  same  manner  as  those  which  were  exposed  to  the 
disinfectant.  The  room  temperature  at  the  time  the  rods  were 
exposed  to  the  action  of  the  disinfectant  was  28°  C.  The  guinea  pigs 
used  for  these  experiments  were  of  uniform  size  and  weight,  the 
average  weight  being  about  375  grams. 

TABLE  19. — Showing  effect  of  1  per  cent  carbolic  acid  on  Bacillus  tuberculosis. 
[Rod  method.    17-day  beef-broth  culture  No.  128  at  38°  C.] 


Days 

No.  of 
guinea 

Material  injected. 

Date  of  inoc- 
ulation 

alive 
after 

Result. 

Pig- 

inocu- 

lation. 

7708 

Culture  not  exposed  to  disinfectant 

July  16,1906 

35 

Died.    Tuberculous. 

7711 

do  ... 

do 

51 

Do. 

7709 

Culture  exposed  to  disinfectant  for  J  minute  

...do... 

12 

Died.     Pneumonia. 

7707 

Culture  exposed  to  disinfectant  for  1  minute 

do 

83 

Died.    Tuberculous. 

7710 

Culture  exposed  to  disinfectant  for  2  minutes  

do     ... 

91 

D>'ed.    Nontubercu- 

lous. 

7584 

Culture  exposed  to  disinfectant  for  5  minutes 

do 

91 

Do. 

The  autopsy  on  guinea  pig  7709,  which  died  within  12  days  after 
inoculation,  showed  consolidation  of  the  anterior  lobes  of  both  lungs 
and  this  animal  probably  died  from  an  intercurrent  pneumonia. 
Had  the  animal  lived  it  would  in  all  probability  have  developed 
tuberculosis,  as  the  animal  next  above  it  in  the  series — guinea  pig 
7707 — inoculated  with  tubercle  bacilli  which  were  given  a  longer 
exposure  to  carbolic  acid,  developed  tuberculosis  and  died  with  well- 
marked  lesions. 

It  will  be  noticed  that  guinea  pig  7707  lived  for  83  days  after  inoc- 
ulation, whereas  the  two  checks — guinea  pigs  1708  and  1711 — died 
within  35  and  51  days  of  the  inoculation.  Taking  an  average  for 
the  two  checks  it  will  be  seen  that  guinea  pig  7707  lived  nearly  twice 
as  long  as  did  the  check  animals  and  it  would  seem  from  this  that 
the  tubercle  bacilli  with  which  guinea  pig  7707  was  inoculated  had 
been  considerably  attenuated  by  an  exposure  of  1  minute  to 
carbolic  acid,  or  else  that  a  large  number  of  the  bacilli  were  killed, 
thus  reducing  the  dose  of  live  bacilli  which  the  animal  received  and 
consequently  prolonging  the  course  of  the  disease. 

At  the  time  guinea  pigs  7710  and  7584  died  a  number  of  guinea 
pigs  were  dying  from  unknown  causes,  but  careful  autopsies  on  these 
animals  failed  to  reveal  any  traces  of  tuberculosis  and  it  would 
see'm  that  the  tubercle  bacilli  with  which  these  animals  were  inocu- 
lated had  been  completely  killed  by  the  carbolic  acid. 


\    M.IK    OK    LUJI  "K    CRKSOI.IS    COMI'OSITCS. 


TMII  I    'JU  ,  il'x-l  i>J  I  JUT  n  nt  liijtinr  rrrsnlm  COWI/KMI/I/*  (crttol  187°  to 

on  linrilluit  tiilxrnilosu. 

|ltiH|  inplhiMl.     |7^!ny  l«vf-l>r..tli  ciilturr  N..   IJMit  38°  C.) 


(\  > 


No.  of 
. 
pig. 

MntiTiiil  Inj-  '•  I 

l>«t«of 
inoculation. 

Dm 

•live 

aft.  r 
Inncti- 

1.  Hi.  .n. 

Remit. 

I'llUlirr  not  eXpnmM  Id  .IiMiifii't.uil  

Juno    fl,180» 

41 

KIlliMl.    TuUTviil.Mi- 

7517 

do  

41 

7530 

Culture  vxpoaed  l<>  'liiinfii-tunt  (<>r  ;  nun. 

do  

41 

Kllll-l         NnlltlltHTT-U- 

7516 

do  

...do... 

41 

llMIH. 

|... 

7523 
7515 

Ciiltun-  i<.\|x>fted  lodlalnfivtiitit  f«>r  1  nun  . 
do  

do  
...do... 

42 
42 

[)., 

Do. 

7534 

Ciiltun-  oxposrd  to  disinfectant  t«r  J  minute*... 

...do... 

42 

!>.. 

7514 

do  

...do... 

42 

Do 

7513 

Culture  exposed  to  diainfivtatit  fur  5  minutes..  . 
.do.. 

do  
do  

33 
40 

Died.       NontuU-n-u- 
lou*. 
Do. 

In  the  experiment  recorded  in  Table  20  the  two  check  animals — 
guinea  pigs  7525  and  7517 — both  showed  well-marked  lesions  of  tuber- 
culosis at  the  end  of  6  weeks,  whereas  none  of  the  animals  inoculated 
with  tubercle  bacilli  which  had  been  exposed  to  liquor  cresolis  com- 
positus  (cresol  187°  to  189°  C.)  showed  any  trace  of  tuberculosis. 

Comparing  Tables  19  and  20,  we  find  that  it  required  an  exposure  of 
two  minutes  to  1  per  cent  carbolic  acid  to  kill  B.  tuberculosis,  whereas 
an  exposure  of  one-half  minute  to  1  per  cent  liquor  cresolis  compositus 
was  sufficient  to  accomplish  the  same  result.  In  other  words,  liquor 
cresolis  compositus  (cresol  187°  to  189°  C.)  killed  B.  tuberculosis  in 
about  one-fourth  the  time  required  by  the  same  strength  of  carbolic- 
acid  solution. 

• 

EXPERIMENTS  WITH  BACILLUS  ANTHRACIS. 

In  all  of  the  preceding  tests  purely  vegetative — i.  e.,  nonspore- 
bearing — micro-organisms  were  used,  and  it  was  shown  that  liquor 
cresolis  compositus  Is  strongly  germicidal  for  these  organisms,  viz, 
Bacillus  pyocyaneus,  B.  cholerse  suis,  B.  coli  communis,  B.  typho&us, 
B.  tuberculosis,  and  Staphylococcus  pyogenes  aureus. 

The  spore-bearing  micro-organisms,   by   reason   of   their  spores, 

possess  a   1 1  UK  1 1   lii-jliiT  derive  « >f  rr-Ul  a  lire  t«>  Imt  li  clirinical  ami  |ih\  -- 

ical  agents  than  the  purely  vegetative  micro-organisms,  and  for  this 
reason  it  seemed  advisable  to  determine  the.  germicidal  efficiency  of 
liquor  cresolis  compositus  for  such  an  organism.  The  following  tests, 
therefore,  were  made  with  Bacillus  anthracis,  the  spores  of  which  are 
highly  resistant  to  most  chemical  disinfectants. 

The  cultures  used  in  these  tests  were  examined  microscopically 
before  the  tests  were  made,  and  showed  an  abundance  of  spores. 


EXPERIMENTS    WITH    BACILLUS    ANTHRACIS. 


23 


TABLE  21. — Showing  effect  of  liquor  cresolis  compositus  on  Bacilhts  anlhracis. 
[Rod  method.    10-day  agar  culture  at  38°  C.    Room  temperature,  28°  to  30°  C.] 


Disinfectant. 

Strength 
of  solution. 

Result  of  exposure  to  disinfectant  for  — 

5 
minutes. 

30 

minutes. 

1 
hour. 

3 
hours. 

6 
hours. 

24 
hours. 

Liquor  cresolis  compositus  con- 
taining— 
Cresol  I  

5  per  cent.. 
6  percent. 
8  per  cent. 
5  per  cent. 
6  per  cent. 
8  percent. 

+ 
+ 
+ 
+ 
+ 
+ 

+ 
+ 

+ 
+ 
+ 
+ 

+ 
+ 

+ 
+ 

+ 
+ 

+ 

+ 

+ 
+ 

+ 
+ 

+ 
+ 

Do 

Do     .                 

Cresol  II  

Do 

Do  

+  means  growth;  —  means  no  growth. 
The  subcultures  were  incubated  for  10  days  at  38°  C.. 

TABLE  22. — Showing  effect  of  liquor  cresolis  compositus  on  Bacillus  anthracis. 
[Rod  method.    10-day  agar  culture  at  38°  C.    Room  temperature,  25°  C.] 


Disinfectant. 

Strength  of 
solution. 

Result  of  exposure  to  disinfectant  for— 

5 
minutes. 

30 

minutes. 

1 
hour. 

3 
hours. 

6 
hours. 

24 

hours. 

Liquor  cresolis  compositus  con- 
taining— 
Cresol  187°  to  189°  C 

6  per  cent... 
do 

+ 
+ 
+ 

+ 

+ 
+ 

+ 
+ 

+ 

+ 
+ 
+ 

+ 
+ 
+ 

- 

Cresol  195°  to  199°  C. 

Cresol  200°  to  203°  C  

do  

+  means  growth;  —  means  no  growth. 
The  subcultures  were  incubated  for  10  days  at  38°  C. 

From  Tables  21  and  22  it  will  be  seen  that  for  the  destruction  of 
anthrax  spores  much  stronger  solutions  of  liquor  cresolis  compositus 
would  be  required  than  for  the  purely  vegetative  micro-organisms. 

In  these  tests,  owing  to  the  well-known  resistance  of  anthrax 
spores,  the  lengths  of  exposure  to  the  disinfectant  were  made  longer 
than  in  the  case  of  the  purely  vegetative  micro-organisms,  and  the 
results,  therefore,  were  not  so  sharp  and  definite  as  with  the  latter. 
Thus,  in  Table  21,  we  fail  to  see  any  difference  in  the  germicidal 
efficiency  of  solutions  of  liquor  cresolis  compositus  made  from  Cresol 
I  and  Cresol  II,  whereas  in  the  case  of  the  vegetative  inicro-organ- 
isms  liquor  cresolis  compositus  made  from  Cresol  II  was  found  to 
be  the  more  efficient.  Also,  in  Table  22  we  fail  to  note  any  difference 
in  the  germicidal  efficiency  of  solutions  of  liquor  cresolis  compositus 
made  from  cresols  of  different  boiling  points,  whereas  these  solutions 
showed  marked  differences  in  germicidal  efficiency  when  tested  on 
the  vegetative  micro-organisms.  With  stronger  solutions  and 
shorter  lengths  of  exposure,  differences  in  the  germicidal  efficiency  of 
the  various  solutions  of  liquor  cresolis  compositus  tested  would  no 
doubt  have  been  noted  for  the  anthrax  spores  as  well  as  in  the  case 
of  the  vegetative  micro-organisms. 


24        1. 1  i:\lirm.\L    VALUE   OF    Mi/l»>K    »  KI-X'i.is   OOMPO8ITU8. 

A-^  llu-  carbolic-acid  coefficient  ut  li<|in.r  crc^oli-,  OOmpOflltlM  for 
anthrax  spores  \\ns  not  determined,  \\e  can  not  make  a  companion 
in  thi>  instance  between  lujnor  cresol  is  compo-itus  and  carhoiic  arid. 

SUMMARY  OF  RESULTS. 

(1)  Liquor  <TCM>|I>  compo»it  i;v  i>  ^i  rongly  ^'cnnicidal  for  tlic  fol- 
lowing   iiiicro-or^anisins:    /lurillns    jtiftH-i/nni  UN,    J>.    clmlcrx   suit,    /'>. 
coli    com  m  mi  i*,    I!.    t>/]>ho8U8,    Ji.    tuberculosis,    and    Staphylococcus 
pyogtm*  (iur> 

(2)  The  gennickU]  ellicicncy  of  li(|iior  crosolis  compositus  increases 
with  tin'  boiling  point  of  the  cresol  it  contains,  and  solutions  of  liquor 
cresoli^  compositus  ma<lc  from  the  higher-boiling  cresols — i.  c..i-n-«>U 
which    approximate    paracresol    and    inetacresol     arc     both    much 
stronger  germicides  than  liquor  cresolis  compo>itus  made  from  a  lo\v- 
boiling  oresol,  which  approximates  orthocresol. 

(3)  Liquor  cresolis  compo>itus  made  from  commercial  cresols  may 
be  expected  to  vary  somewhat  in  germicidal  elliciency,  owing  to  varia- 
tions in  the  boiling  points  of  the  cresols  it  contains.     This  variation, 
however,  does  not  render  it  unreliable  as  a  disinfectant,  as  a  solution 
of  liquor  cresolis  compositus  made  from  the  lowest-boiling  and  lea-t- 
active  cresol  was  found  to  possess  stronger  gennicidal  proj>erties  than 
carbolic  acid. 

(4)  The  gennicidal  value  of  liquor  cresolis  compositus  made  from 
cresol    which    boils    at    a    temperature    approximating    orthocresol 
(187°  to  189°  C.)  is  nearly  one  and  one-half  times  greater  than  carbolic 
acid. 


